Calcium naphthenate in hydrocarbon extraction



' rection.

Patented Aug. 28, 1945 .UNlTEi) s'rATss PATENT. orrics CALCIUMNAPHTHENATE 1N HYDRDOAB- BON EXTRACTION Mar-inns Buis, Ellesmere Port,and Leonard Belchetr, Ince, near Chester, England, assignors to ShellDevelopment Company, San Francisco, Calif a corporation of DelawareDrawing. Application June 28, 1944,

Serial No. 542,808

7 Claims. (01. ice-1s) i a contacting a liquid mixture to be extractedwith a liquid selective solvent for one oi the components of thatmixture either in a mixer and settler or countercurrently through avessel such as a packed tower. The solvent is not completely misciblewith the mixture under the conditions of the extraction, so that twoliquid phases are formed which are separated and the solvent in eitheror both of these phases is then removed and may be re-cycled for contactwith more of the une'xtracted mixture;

Previously, wax suppressors such as aluminum and magnesium stearates andpalmitates and magnesium and lead naphthenates have been used inprocesses for the liquid solvent extraction of hydrocarbon oilscontaining waxes, but calcium naphthenate was not suggested for suchprocesses because it is not a wax suppressor as will be seen fromExample VI below.

- of inverting the emulsion tendency, thereby in- It is the primarypurpose of this invention to improve the separation time, or settlingtime, be-

tween the solvent and hydrocarbon phases pro-.

duced in such liquid solvent extraction processes.

irrespective of whether the hydrocarbon does or does not contain wax.

This invention, as previously stated, comprises 4 is usually thelimiting factor. Or else for a given,

throughput the yield and/or quality of the products may be improved dueto reduced carryover.

' In an extraction tower the number of theoretical extraction stages mayincrease materially for a given feed rate because of a reduced tendencyto carry finely suspended The amount of calcium naphthenate required toincrease the separation time depends upon several factors, namely: thetype of solvent employed in the process: the type of mixture to beseparated in theprocess; the components in the mixture which aflectemulsibility; the molecular weight and the acid eq ivalent of thecalcium droplets in the wrong diamount is required to produce a givensett time, than if acids of higher acid number had' been used. As arule, oil suspended in the solvent separates much more slowly thansolvent suspended inch, and if too great an amount of calciumnaphthenates is used, it will have'the effect creasing the stability ofhydrccarbonin solvent emulsions and defeating the purpose of thisinvention. Genera y, suitable amounts of calcium naphthenates rangebetween about .01% and 1% and preferably between .02 and 15% by weightof the hydrocarbon in the mixture.

The calcium naphthenate may be derived from any suitable source. It ismost easily produced by simply neutralizing ngphthenic acids with lime.

The calcium naphthenate-may be added continuously 'or intermittentlyeither to the hydro carbon or to the solvent, or to both.

In the course of the extraction, mcst of the 'naphthenate goes into theextract phase from which it may be recovered, and, if desired, bereturned to the extraction zone. A small portion may remain in theraiilnate.

Depending on the use of the rafllnate oil or extract oil or both, it maybe necessary to remove all or part of the naphthenate therefrom, if suchremoval has not occurred as a result of removal of the solvent from therespective phases. Re-

moval can normally be achieved by means such as distillation, thenaphthenate remaining in the;

residue: or acidification and distillation, in which case the naphthenicacid may distill overhead: or

clay treatment; the naphthenate being retained by the clay; etc.

Insome cases, the presence of the napthenate in the extracted oil may bedecidedly beneficial. Thus, in lubricants-it acts as a detergent, inspray process of this invention, particularly those mixtures derivedfrom petroleum including gasolines, kerosenes, spray oils, gas oils,-Diesel fuels, lubrieating oils, etc.

Some suitable liquid selective solvents which may be employed in theseparation of hydrocarbon mixtures are: phenol, cresylic acids, alkylphenol mixtures, aniline, alkyl aniiines, diphenyl amine, ditolylamines. carbitols (diethylene glycol monoethers) such as methyl, ethyl,propyl carbitols, chlorinated dialkyl others such as betabetadichlor-ethyl ether, nitrobenzene, nitrotoluene. nitroxylenes.na'ohthois a'lkvl 'nanhthnle benzophenone, phenyl tolyl ketone,diphenylene ketone, alkyl phthalates such as dimethyl phthalate, alkylsalicylates such as methyl salicylate, benzyl alcohol, benz chlorides,i. e., benzyl, benzal, benzo-chlorides, benzonitrile, diphenyl oxide,substituted diphenyl oxide which may contain amino, nitro, hydroxy,etc., radicals; ditolyl oxide, substituted ditolyl oxides which maycontain amino, nitro,- hydroxy, etc, radicals, hydroxy pyridine, nitropyridine, chlorinated pyridines, substituted quinolines, isoquinoline,chlorinated quinoline, such as hydroxy quinoline, S-nitroquinoline,qulnaldine, beta-alpha picoline, alpha picoline, refinery N-bases,tetrahydrofurfuryl alcohol, fur

furyl alcohol, furfural, monoglycerol ethers such Exmu I Several samplesof a Colon waxy distillate lubricating oil were extracted with furfuralin the presence of different amounts of calcium. naphthenate and in theabsence of calcium naphthenate. The influence of the concentration ofthe calcium naphthenate having a relatively high molecular weight and anacid value equivalent to 115 mgs. of KOH per gm. on such extracti nmixtures is shown in the table below:

Percent calcium naphthenste Type emulsion Nil Stable oil in iurfurai.cor-0.03% w/w Coagulation and rapid settling. 3.05 o Incipient iuriuralin oil. Above 0.1% Stable furiuml in oil.

ExAmLn II Two samples of Colon waxy distillate lubricating oil wereextracted with furfural at different solvent-to-feed ratios and in theabsence and in the presence of calcium naphthenate to obtain a,substantially identical product. As can be seen from the table below,the presence of :alcium naphthenate materially reduces thesolvent-to-feed ratio necessary to obtain the given V. I. (viscosityindex) from the same lubricating 0.016% cal- No calcium ciumnephnaphthenate thenate added used to waxy distillsto lolvent ratio4x200 3X200 2. L of waxy rnfl 1.4674 1. 4682 LLoiwsxy mfl 113 116 I. 1.above rail. alter dewaxing s 97 1 R. L -reirsctive index.

EXAMPLE III.

Several samples of an East Texas dewaxed disillate lubricating oil wereadmixed with dimethyl sulfolane and the settling times were determinedPercent by wt. calcium nspbthenate Settling time calculated on the oilin minutes EXAMPLE IV Two samples of a Mid-Continent dewaxed distillate(250 S. U. vis. at 100 F.) were contacted with 150% by wt. phenols and250% by wt. propane in a glass bomb at a temperature of F. to simulateconditions present in a DuoSol ex traction process. One of the samplescontained no calcium naphthenate and the other did contaln 33% by wt.-ofcalcium naphthenate in the distillate. It was found that the separationtimes between the solvent and the oil were 22 seconds and 14 secondsrespectively. The resulting phases were then, tested to determine thecontent of the phenol in each phase, and it was found that the samplecontaining the calcium naphthenate had less phenol in the raflinate thanthe other sample, as seen by the following table:

Phenol contents, percent w.

Rafllnate Extract {1) No calcium naphthenate 44. 4 90. 5 2) 0. 5%calcium nsphthenate v. 38. 6 91. 5

EXAMPLEV Three other samples of dewaxed Mid-Continent lubricatingdistillate (250 S. U. vis. at F.) were tested similarly to the samplesin Example V above and more data was obtained as seen in the followingtable:

Efieci' of calcium naphthenate on acid-retention Of the raiflnate andextract layers in DuoSol extraction Several other-samples were preparedboth with a waxy and the dewaxed Mid-Continent distillate lubricatingoil (250 SUV at 100 F.) and subjected to tests similar to those discloseabove in Examples IV and V. It was found that the presence of calciumnaphthenate had substantially no effect (within experimental error) onthe settling time or the pour point of the wax containing distillate asseen from the following two tables:

Eflect of calcium naphthenateon acid settling rate in DuoSol extractionSettling time, minutes Percent Ca naphthenate in distillate 0.0 0.0670.33 Dewaxed M-C 250 distillate 25 20 Waxy M-C 25c disti1late 27 23asasnes 1. In a liquid-liquid solvent extraction process for theseparation of a hydrocarbon mixture with a selective solvent, theimprovement comprising carrying out said extraction in the'presence ofbetween about .01% and 1% by wt. of calcium naphthenate in saidhydrocarbon mixture, said asses-=- amount being insumcient tocause astable sol- 20 vent-in-hydrocarbon emulsion.

2. The process 0! claimi, wherein said hydrocarbon mixture containsparaflin wax;

3. The process oi claim 1, wherein said lxvdrocarbon mixture is freeirom wax.

4. The process of claim 1, wherein said hydrocarbon mixture is alubricating oil.

5. The process of claim 1, wherein said solvent is iuriural. a

6. The process of claim 1, wherein the amount 0! calcium naphthenai'e isbetween about '.02% and .5% by wt.

' 'I. In a DuoSol extraction process for the separation of a hydrocarbonoil with a mixed solvent comprising a phenol and propane, theimprovementcomprising carrying out said extraction in the presence of .01% and 1%by wt. of calcium naphthenate, said amount being insumcient'to cause astable aolvent-in-hydrocarbon emulsion;

MARINUS BUIS. LEONARD BELCHETZ.

